SiOH-containing organosilicon compounds are excellent plasticizers for silicone rubbers. Organosilicon compounds of this type are exemplified by diorganosilanediols such as diphenylsilanediol, etc., and by organosiloxane oligomers such as trimethylsiloxydiphenylsilanol, alpha,omega-dihydroxymethylphenylsiloxane oligomer, alpha,omega-dihydroxydiphenylsiloxane oligomer, and others.
In Japanese Patent Application Number Hei 3-336078 [336,078/1991] the present inventors have already proposed a method for the preparation of triorganosiloxydiphenylsilanol. The method for the preparation of triorganosiloxydiphenylsilanol proposed in Japanese Patent Application Number Hei 3-336078 characteristically consists of the following: a first step in which triorganochlorosilane is very carefully hydrolyzed to give triorganosilanol; a second step in which a reaction mixture is prepared by a dehydrochlorination reaction between the triorganosilanol and a diphenyldihalosilane; a third step in which triorganosiloxydiphenylhalosilane is purified from the resulting reaction mixture; and a fourth step in which the triorganosiloxydiphenylhalosilane is very carefully hydrolyzed. However, the method proposed in Japanese Patent Application Number Hei 3-336078 suffers from a complicated, four-step reaction scheme and from a low overall yield of the triorganosiloxydiphenylsilanol.
It is an object of the present invention the introduction of a high-yield method for the preparation of single-terminal SiOH-endblocked organosiloxane oligomer.